Developing device for copying apparatus of the diazo type

ABSTRACT

A device comprising a developing liquid quantity control member operatively associated with a developing liquid supply roller for adjusting to an optimum level the quantity of a nonvolatile, concentrated developing liquid supplied to a developing position between a developing liquid applicator roller and a pressure applying roller so as to apply an essential minimum of the developing liquid to an exposed photosensitive sheet of the diazo type fed to the developing position. There is also provided a developing liquid removal member disposed posteriorly to the developing position for removing from the periphery of the developing liquid applicator roller any excess developing liquid which might otherwise remain thereon.

United States Patent 1191 Yamashita et a].

[451 Apr. 1, 1975 DEVELOPING DEVICE FOR COPYING APPARATUS OF THE DIAZOTYPE [75] Inventors: Tadashi Yamashita, Yokohama;

Yasuhiro Takahashi, Tokyo, both of Japan [73] Assignee: Ricoh Co., Ltd.,Tokyo, Japan [22] Filed: June 26, 1973 21 Appl. No.: 373,892

[30] Foreign Application Priority Data July 15, 1972 Japan 47-71090 [52]Cl 354/318, 118/203, 118/249, 118/262, 355/10 [51] Int. Cl. G03d 5/00[58] Field of Search 95/89 R, 89 A, 89 G;

[56] References Cited UNITED STATES PATENTS 2.605.684 8/1952 Nagels eta1]. 95/89 A 2,676,563 4/1954 Montgomery et al. 95/89 R UX 2,887,0295/1959 Druce 95/89 R SOL 3,580,158 5/1971 Scholle et a1. 95/89 G3,687,049 8/1972 Koch et al 95/89 R FOREIGN PATENTS OR APPLICATIONS302,567 10/1968 Sweden 355/10 Primary ExaminerFred L. Braun Attorney,Agent, or Firm-Cooper, Dunham, Clark, Griffin & Moran [57] ABSTRACT Adevice comprising a developing liquid quantity control memberoperatively associated with a developing liquid supply roller foradjusting to an optimum level the quantity of a nonvolatile,concentrated developing liquid supplied to a developing position betweena developing liquid applicator roller anda pressure applying roller soas to apply an essential minimum of the developing liquid to an exposedphotosensitive sheet of the diazo type fed to the developing position.There is also provided a developing liquid removal member disposedposteri'orly to the developing position for removing from the peripheryof the developing liquid applicator roller any excess developing liquidwhich might otherwise remain thereon.

12 Claims, 11 Drawing Figures i 1 iii-R 1 m5 SHEET 1 0F 5IIIIIIIIIIIIIIIIII/ I I I I I I I I I I I I I I I I 0 a PERIPFERALVELOCITY OF SUPPLY ROLLER TEI-I'IEIIIII I I975 I 8755.581

QUANTITY OF DEVELOPING LIQUID APPLIED fifiRLHRQEEXFEiQ? fiE T0PHOTOSENSITIVE SHEET OF A4 SIZE SLZT 2 0F 5 mg FIG. 5

0 6 I00 e/ "r 0 I00 200 300 400 500 600 "1 PERIPHERAL vEL0cITY OFAPPLIcAToR ROLLER 9 PERIPHERAL VELOCITY OF APPLICATOR ROLLER sczmms Cl gPIC-3.7 E 80- E0 6 3g 60- EE F c c 3 J- PERIPHERAL VELOCITY OF suPPLYRoLLER mg g L PIC-3.8 3 0 h o 5 I60 9g 0 E ma; o -cL O 320- RE g O L I ll I I l PERIPHERAL VELOCITY OF SUPPLY ROLLER BACKGROUND OF THE INVENTIONThis invention relates to developing devices for copying apparatus ofthe diazo type, andmore particularly it is concerned with a developingdevice of the type described whereby a diazo photosensitive sheet of thebinary system exposed to an optical image of an original is developed byapplying a very small quantity of a developing agent consisting of anorganic amine and other elements.

In addition to a dry developing agent and liquid developing agent, adeveloping liquid consisting of an organic amine and other elements andusually in the form ofa nonvolatile, concentrated developing liquid isused to develop optical images of originals formed by exposure on diazophotosensitive sheets. The use ofthis type of developing liquid isadvantageous in that the optical images can be developed by applying avery small quantity of the developing liquid so that the photosensitivesheets are dry when the images thereon are developed in spite of thefact that the developing liquid is used. A developing system using thistype of developing liquid is described, for example, in Japanese Pat.Pub. No. Sho 44-24998.

The quantity of the developing liquid required in this developing systemfor developing optical images formed on diazo photosensitive sheets isonly 60 to I50 mg., when the sheets are of a particular size, which isabout one tenth the quantity of the developing liquid required inconventional developing systems using a liquid developing agent. Thepaucity of the developing liquid required for performing this developingoperation permits the photosensitive sheets to be in a dry state afterdeveloping as if a dry developing agent were used.

In carrying out development by this developing system, it is essentialthat the very small quantity of the developing liquid used be uniformlyapplied to the photosensitive surface of the photosensitive sheet inorder to achieve satisfactory result. If the developing liquid is notevenly applied to the photosensitive surface of the photosensitivesheet, the photosensitive sheet may show a change in color with time.Since the developing liquid is applied to the photosensitive surfaceonly, if the quantity of the developing agent applied to thephotosensitive surface is larger than is necessary, the photosensitivesheet may curl up with the photosensitive surface facing inwardly whendeveloped, so that the photosensitive sheet may not be of any practicalvalue.

Difficulty has hitherto been experienced in this developing system inapplying a very small quantity of the developing liquid evenly on aphotosensitive sheet to form a layer of the developing liquid of auniform thickness. It has hitherto been customary to form a layer of thedeveloping liquid of a uniform thickness on an applicator roller by somemeansand to bring the exposed photosensitive surface of a diazophotosensitive sheet into pressing engagementtherewijtli so as todevelop the image on the photosensitive surface.

In forming a layer of the developing liquid on an applicator roller, ithas hitherto been customary to use a roller for adjusting the thicknessof the layer to any level as desired or to usea doctor blade for forminga layer of a uniform thickness. Thefuse of the roller or doctor bladehas problems which are hard to obviate.

More specifically, the use ofthe roller has the problem of how topreclude deflection of the roller or to improve the degree of precisionwith which the roller is made. The peripheral velocity of the roller isalso a factor influencing the quantity of the developing liquid appliedto the applicator roller. The method of using a doctor blade for forminga coat of the developingagent of a uniform thickness makes it necessaryto fabricate the front end of the doctor blade with a considerably highdegree of precision. Besides, the manner of application of the doctorblade to the applicator roller and the degree of coarseness of thesurface of the applicator roller tend to affect the adjusments of thequantity of developing liquid applied to the applicator roller.Frictional dragging of the doctor blade on the applicator roller tendsto cause wear and damage thereto, sometimes resulting in the applicatorroller oscillating in small amplitude. By and large, the use of a doctorblade for adjusting the quantity ofthe developing liquid on theapplicator roller is more advantageous than the use of a roller forforming a layer of the developing liquid of a uniform thickness on theapplicator roller in that the operation is less affected by speed andcan be performed by using a lower pressure at which it is maintained inengagement with the applicator roller.

SUMMARY OF THE INVENTION This invention has as its object the provisionof a developing device for copying apparatus of the diazo type using adeveloping liquid of high efficiency consisting of an organic amine andother elements which device comprises a developing liquid quantitycontrol member operatively associated with a developing liquid supplyroller having a relatively coarse peripheral surface for adjusting thequantity of the developing liquid supplied to a developing liquidapplicator roller maintained in pressing contact with the developingliquid supply roller to an optimum level so as to form on the peripheryof the latter a layer of the developing liquid of a uniform thicknesswhich is insusceptible to changes in the peripheral velocity of thedeveloping liquid applicator roller.

According to the invention, there is provided a developing device forcopying apparatus of the diazo type comprising a developing liquidquantity control member operatively associated with a developing liquidsupply roller for adjusting to an optimum level the quantity of anonvolatile, concentrated developing liquid supplied to a developingposition between a developing liquid applicator roller and a pressureapplying roller so as to apply an essential minimum of the developingliquid to an exposed photosensitive sheet of the diazo type fed to thedeveloping position. There is also provided a developing liquid removalmember disposed posterior to the developing position for removing fromthe periphery of the developing liquid applicator roller any excessdeveloping liquid which might otherwise remain thereon. The invention iseffective to form on the periphery of the developing liquid applicatorroller a layer of the developing liquid of a uniform thickness at alltimes so that the features of the nonvolatile, concentrated developingliquid can be brought into full play.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of thedeveloping device for copying apparatus of the diazo type comprising oneembodiment of the present invention;

FIG. 2 and FIG 3 are sectional views of the developing device forcopying apparatus of the diazo type comprising second and thirdembodiments of the invention respectively;

FIG. 4 is a diagram showing curves representing the quantities of thedeveloping liquid applied to the photosensitive sheets as a bodyfunction of supply roller speed using different embodiments ofdeveloping device;

FIG. 5 to FIG. 8 are diagrams showning curves representing thequantities of the developing liquid applied to the photosensitive sheetsas a function of applicator roller speed; and

FIG. 9 to FIG. 11 are sectional side views of different types ofmechanism in concrete form for operating the device according to theinvention.

DESCRIPTION OF PREFERRED EMBODIMENTS FIG. 1 shows one embodiment of thedeveloping device according to the invention. A liquid supply roller 1,which is adapted to be rotated in the direction of an arrow a by a drive(not shown), is made of a nonporous material or rubber of 40to 60 ofhardness and an average surface coarseness of 3 to 5 [.LRZI. Thedeveloping liquid supply roller 1 has a lower portion of its peripheryimmersed in a nonvolatile, concentrated developing liquid 3 contained ina developing pan 2 and is maintained at an upper portion of itsperiphery in pressing engagement with a developing liquid applicatorroller 4 adapted to rotate in the direction of an arrow h.

A developing liquid quantity control member 5 or a first doctor blade ismaintained in engagement with the periphery of the developing liquidsupply roller 1 in a position which is disposed anterior to orleftwardly in FIG. I of the position in which the developing liquidapplicator roller 4 is maintained in pressing engagement with the supplyroller 1. The developing liquid quantity control member 5 is constructedsuch that the angle at which it is disposed with respect to theperiphcry of the developing liquid supply roller 1 and the degree atwhich it is maintained in pressing engagement with the periphery of thesupply roller 1 can be varied so as to thereby adjust to an optimumlevel the quantity of the developing liquid scooped up by the supplyroller 1 and supplied to the applicator roller 4. Thus the quantitycontrol member 5 is disposed above the liquid level in the developingliquid pan 2.

The developing liquid supply roller 1 is shown and described as havingthe lower portion of its periphery being immersed in the developingliquid 3 in this embodiment. This is not essential, however, and thedeveloping liquid can be supplied to the supply roller either byspraying or other means.

The developing liquid scooped up by the supply roller 1 is supplied to adeveloping position 7 disposed between a pressing roller 6 and theapplicator roller 4 maintained in pressing engagement with each other.The pressing roller 6 is in the form of a metallic roller made as ofstainless steel in this embodiment and rotates in the direction of anarrow 0. Preferably, a series of peripheral grooves or a spiral groovedisposed peripherally of the roller is formed in the roller 4 so as toprevent the developing liquid from being collected between the tworollers and 4. In the developing position 7, the pressing roller 6 ismaintained in line or surface engagement with the applicator roller 4,and an exposed photosensitive sheet 8 is fed to the developing position7 from right to left in FIG. 1.

A developing liquid removal member 9 or a second doctor blade isdisposed posterior to the developing position 7 in which the pressingroller 6 is in engagement with the applicator roller 4. It is maintainedat its forward end in pressing engagement with the periphery of theapplicator roller 4 so as to remove therefrom any excess developingliquid which might otherwise remain thereon. Like the quantity controlmember 5, the developing liquid removal member 9 is constructed suchthat the angle at which it is disposed with respect to the periphery ofthe applicator roller 4 and the degree at which it is maintained inpressing engagement with the periphery of the applicator roller 4 can bevaried as desired.

The developing liquid removal member 9 and the quantity control member 5each have a length which is slightly greater that the width of theperiphery of the supply roller 1 and the applicator roller 4. The reasonwhy the developing liquid removal member 9 is disposed posterior to thedeveloping position 7 is because the layer of the developing liquid onthe portion of the periphery of the applicator roller 4 disposedanterior to the developing position 7 has an optimum thickness by virtueof the presence of the quantity control member 5. It is to be understoodthat the position in which the removal member 9 is disposed may benearer to the developing position 7 than is shown in FIG. 1. However,the position in which the removal member 9 is shown as being disposed inFIG. 1 is a most convenient one from the point of view of removing thedeveloping liquid when the length of the member 9, means for adjustablyfixing the same and the peripheral velocity of the applicator roller 4are taken into consideration.

The developing device constructed as aforementioned is advantageous insupplying the developing liquid from the supply roller 1 to theapplicator roller 4. The physical properties of the developing liquidwill show variations due to changes in the peripheral velocity of therollers and the environmental conditions including temperature. That is,the viscosity of the developing liquid will vary depending ontemperature, and the quantity of the developing liquid scooped up by thesupply roller will vary depending on a change in the peripheral velocityof the roller. This is clearly shown by the results of tests. Morespecifically, curves shown in the diagram in FIG. 4 represent thequantities of the developing liquid applied to the photosensitive sheetsobtained by plotting the quantities of the developing liquid as theordinates against the peripheral velocities of the supply roller as theabscissae. The broken line A represents the quantity of the developingliquid which is adjusted only by using a doctor blade as a developingliquid quantity control member and transferring the developing liquiddirectly from the supply roller to the photosensitive sheet. It will beseen that the quantity increases substantially in proportion to theperipheral velocity of the supply roller. The dash-and-dot line Brepresents the quantity of the developing liquid which is adjusted onlyby transferring the developing liquid from the supply roller to theapplicator roller without the use of a doctor blade. It will be seenthat in this case the quantity is reduced because the time during whichthe developing liquid is transferred to the applicator roller becomesshorter as the peripheral velocity of the supply roller increases. Thus,by suitably combining the aforementioned two control methods with eachother, it will be possible to supply the developing liquid in uniformquantity as shown by the solid line C irrespective of changes in theperipheral velocity of the supply roller. This invention is based on theaforementioned concept. 7

Generally, an increase in the peripheral velocity of the developingliquid supply roller 1 results in an increase in the quantity of thedeveloping liquid supplied from the supply roller 1 after being adjustedby the control member 5. Therefore, if the photosensitive sheet 8 ismoved between the rollers l and 4 in a position disposed immediatelyposterior to the position in which the control member 5 is maintained inengagement with the supply roller 1, the developing liquid will beapplied in a large quantity to the photosensitive sheet. However, if thephotosensitive sheet 8 is brought into contact with the applicatorroller 4 after the developing liquid is transferred from the supplyroller 1 to the applicator roller 4 after being adjusted by the controlmember 5, the quantity of the developing liquid applied to thephotosensitive sheet will be reduced when the peripheral velocity of thesupply roller increases because the quantity transferred to theapplicator roller 4 is reduced and will be increased when the peripheralvelocity of the supply roller decreases because the quantity transferredto the applicator roller is increased.

Because of this, it is possible to apply the developing liquid in asubstantially uniform quantity to the photosensitive sheet 8 by causingthe latter to move through the developing position 7 between theapplicator roller 4 and the pressing member 6 irrespective of changes inthe peripheral velocity of the supply roller 1.

By varying the pressure at which the rollers l and 4 are maintained inpressing engagement with each 7 other, it is possible to control to acertain extent the quantity of the developing liquid transferred fromthe supply roller 1 to the applicator roller 4. It is thus possible toform on the periphery of the applicator roller 4 a layer of thedeveloping liquid of a substantially uniform thickness at all times.Preferably, the applicator roller 4 is made of a non-porous materialwhich suits photosensitive sheets. The material used for making theapplicator roller 4 in this embodiment is rubber having a hardness in arange from 40 to 70 (preferably from 40 to 50) and a mean surfacecoarseness of less than 3 uRa (preferably between 1 and 1.5 ,uRa). Whenthe periphery of the applicator roller 4 has a mean coarseness of above3 p.Ra, the coarseness of the roller unfavorably affects thephotosensitive sheets and lowers the quality of the duplicates produced.

The developing liquid on the applicator roller 4 can be applied bypressure transfer in a quantity which is an essential minimum to thephotosensitive sheet fed to the developing position 7 in which thepressing roller 6 is maintained in line or surface engagement with theapplicator roller 4.

When no photosensitive sheet is fed to the developing position, anyexcess developing liquid on the applicator roller 4 is removed therefromby the removal member 9. Thus, when thedeveloping device is set inmotion, the developing liquid is continuously supplied from the supplyroller 1 to the applicator roller 4. If no removal member 9 wereprovided, the developing liquid supplied and retained on the applicatorroller 4 would become so great in quantity that it would satu-.

rate the periphery of the applicator roller 4 and no more developingliquid would be supplied from the supply roller 1 to the applicatorroller 4. If a photosensitive sheet were fed to the developing position7 at this time, more developing liquid than is necessary would beapplied to the photosensitive sheet by the applicator roller 4, so thatthe duplicate produced would be degraded in quality. In order to avoidsuch phenomenon, the removal member 9 is essential to remove excessdeveloping liquid from the applicator roller 4 and return it to thedeveloping pan 2. The removal member 9 and adjusting member 5 arepreferably made of a resilient material and covered with a material oflow coefficient of friction, such as Teflon, for example.

The supply roller 1 may be rotated at the same peripheral velocity asthe applicator roller 4. The developing liquid can be suppliedsatisfactorily to the applicator roller 4 to form a layer of developingliquid of a uniform thickness thereon even if the peripheral velocity ofthe supply roller 1 is slightly lower than that of the applicator roller4.

FIG. 2 and FIG. 3 shown modified forms of the developing deviceaccording to the invention. In the embodiment shown in FIG. 2, thedeveloping liquid quantity control member 5 is in the form of a squeezeroller 5a, with the rollers 1, 5a, 4 and 6 being maintained in pressingengagement with one another. The developing liquid scooped up by thesupply roller 1 is transferred to the squeeze roller 5a where thequantity of the developing liquid is adjusted to an optimum level beforebeing transferred to the applicator roller 4. The transfer of thedeveloping liquid from roller to roller is carried out continuouslywhile the rollers rotate. For practical purposes, the squeeze roller 5ais required to be fabricated with a considerably high degree ofprecision. The developing position is disposed between the applicatorroller 4 and the pressing roller 6 in this embodiment too. In theembodiment shown in FIG. 3, a roller 9a is substituted for the doctorblade 9 of FIG. 1 as a developing liquid removal member 9.

FIG. 5 to FIG. 8 show the results of experiments carried out on thequantity of the developing liquid applied to the photosensitive sheet 8by the applicator roller 4 as a function of the peripheral velocity ofthe applicator roller. A line D in FIG. 5 represents the weight ofdeveloping liquid transferred to an overlying sheet of twophotosensitive sheets superposed one on the other and fed between therollers 1 and 4. A line E in FIG. 6 represents the quantity of thedeveloping liquid remaining on the applicator roller 4. A line F in FIG.7 shows the rate of transfer of the developing liquid from the supplyroller 1 to the applicator roller 4. A line G in FIG. 8 represents thequantity of the developing liquid on the supply roller 1.

From the data shown in the figures, it will be seen that changes in thequantity of the developing liquid are very small and the transfer of thedeveloping liquid from the supply roller 1 to the applicator roller 4can achieve satisfactory results in forming a layer of the developingliquid of a uniform thickness on the latter, although no definitiverelation is established between the peripheral velocity of the supplyroller and the quantity of the developing liquid applied to thephotosensitive sheet because of the fact that the efficiency of thedoctor blade 5 is higher than expected.

In order to prevent deformation of the supply roller 1 and theapplicator roller 4, the control member 5 and the removal member 9 arepreferably released from engagement with the rollers l and 4respectively or maintained in light engagement therewith when thedeveloping device out of service. The rollers 6. 5a and l are preferablyreleased from pressing engagement with one another when the developingdevice is out of service. The pressure at which the removal member 9 isin engagement with the applicator roller 4 is preferably the same as orhigher than the pressure at which the control member 5 is in engagementwith supply roller 1.

Accordingly, the developing device according to the invention isoperated by a mechanism which comprises a solenoid adapted to beenergized when a start switch (not shown) is turned on so that therollers may be brought into pressing engagement with one another and thecontrol and removal members may be brought into pressing engagement attheir front ends with the respective rollers. Such mechanism will now bedescribed with reference to embodiments shown in FIG. 9 to FIG. 11.

The embodiment shown in FIG. 9 utilizes a togglejoint and is constructedsuch that upon energization of the solenoid SOL a link 11 is pivotedcounter clockwise at one end about an immovably pin 12 and the otherlink 13 is guided by another immovable pin 14 received in a slot 13aformed in the link 13, so that a pressure applying arm 15 is movedupwardly.

More specifically, the solenoid SOL has connected thereto an actuatorSOLo which is pulled by the solenoid SOL upon energization thereof andwhich has a pin 16 riding in a transverse slot 16a therein andsupporting the link 11 at the end opposite that which is pivotallysupported by the immovable pin 12 as aforementioned. The pin 16 alsosupports the link 13 at one end which is symmetrically arranged withrespect to the link 1]. the link 13 being formed at the other endportion with the slot 13a for receiving therein the immovable pin 14 asaforementioned.

By the aforementioned arrangement, the link 11 will pivot counterclockwise in FIG. 9 about the pin 12 when the actuator SOLo is pulledtoward the solenoid SOL, so that the pin 16 will move along an areleftwardly in FIG. 9 and the link 13 will move upwardly as guided by thepin 14 received in the slot 13a. The link 13 moves by its upper end thepressure applying arm 15 upwardly. The pressure applying arm 15 ispivotally supported by a pressure applying roller shaft 17 and includesa free end portion 15:! extending above the upper end of the link 13 andmoved downwardly about shaft 17 by the biasing force of a spring 18, sothat a bent portion 15b formed on the free end portion 15a is maintainedin contact with the upper end of the link 13. The pressure applying arm15 has firmly secured to an end portion thereof which is disposed at theopposite end from the free end portion 15: a pressure applying rollersupporting member 19 supporting a pressure applying roller 20. Thepressure applying roller 20 is adapted to bear against the pressingroller 6 so as to bring the roller 6 into pressing engagement with theapplicator roller 4 and to bring the roller 4 into pressing engagementwith the supply roller lfwhen the link 13 moves the pressure applyingarm 15 upwardly.

On the other hand, a bar 21 extending toward the rollers is connected atone end 21a to thefreeend portion 15a of the pressure applying arm 15through a pin 22 and supports at the other end 21h oneend of connector23 through a pin 24, the connector 23 being firmly secured at the otherend to a rotary shaft 25. The rotary shaft 25 has secured thereto asegmental gear 26 which in turn has secured thereto a blade mountingmember 27. The developing liquid removal member 9 in the form of adoctor blade is secured at its base to the mounting member 27 and has aforward end which is disposed near the periphery of the applicatorroller 4 and which is adapted to be brought into pressing engagementwith the periphery of the applicator roller 4 when the segmental gear 26pivots counterclockwise about the shaft 25 which angularly rotates inthe same direction as the segmental gear 26.

The segmental gear 26 is maintained in meshing engagement with anothersegmental gear 28 pivotally supported by a shaft 29 and has a mountingmember 30 secured thereto. The developing liquid quantity control member5 in the form of a doctor blade is secured at its base to the mountingmember 30 and has a forward end which is disposed near the periphery ofthe supply roller 1 and which is adapted to be brought into pressingengagement with the periphery of the supply roller 1 when the segmentalgear 28 pivots clockwise about the shaft 29.

Operation of the embodiment constructed as aforementioned will now bedescribed. Upon energization of the solenoid SOL the actuator SOLo ispulled toward the solenoid SOL and moves leftwardly in FIG. 9, so thatthe link 11 pivots counterclockwise about the pin 12 under the action ofpin 16. This causes the pin 16 to move in an arc leftwardly and push thelink 13 so that the latter moves upwardly while being guided by the pin14 received in the slot 13d. This causes the front end edge of the link13 to push and move the bent portion 15b of the pressure applying arm15, so that the arm 15 pivots clockwise about the pressure applyingroller shaft 17. This causes the pressure applying roller 20 to push thepressing member 6 downwardly, so that the pressing member 6 bearsagainst the applicator roller 4 and the applicator roller 4 bearsagainst the supply roller 1.

On the other hand, clockwise pivoting of the pressure applying arm 15also causes, through the bar 21, the connector 23 to pivotcounterclockwise about the shaft 25 which angularly rotates about itsown axis. Counterclockwise pivoting of the connector 23 causes thesegmental gear 26 to pivot counterclockwise about the shaft 25 whichangularly moves in the same direction the segmental gear 26. so that thefront end of the removal member 9 is brought into pressing engagementwith the periphery of the applicator roller 4. Counter clockwisepivoting of the segmental gear 26 causes the segmental gear 28 inmeshing engagement with the segmental gear 26 to pivot clockwise aboutthe shaft 29 so as to bring the front end of the control member 5 intopressing engagement with the periphery of the supply roller 1.

The embodiment shown in FIG. 10 employs a hydraulic pressure cylinderand piston arrangement in place of the toggle-joint for causing thepressure applying arm 15 to pivot. More specifically, the actuatorconnected to and pulled by the solenoid SOL is in the form of an arm 31which is supported at a base 31a by an immovable member 32 through a pin33 and connected at its front end'3'1b to the solenoid SOL. Connected tothe arm 31 between the opposite ends thereof is a piston rod supportingat its end a piston 34 received in a cylinder 35 for compressing thefluid contained therein. Another cylinder 37 is disposed below the bentportion 15b of the pressure applying arm 15 which is adapted to bepushed and moved upwardly by a piston rod supporting at its end a piston36 received in the cylinder 37 for compressing the fluid containedtherein. The cylinders 35 and 37 are maintained in communication witheach other through a pipe 38'. Other parts of the mechanism aresubstantially similar to the corresponding parts of the mechanism shownin FIG. 9 except for the arrangement in which the connector 23 and thepressure applying arm 15 are connected to each other by a compressionspring 39 and the pin 24 planted on the connector 23 is adapted to bepushed and moved by an arm 15c projecting from the lower edge of thepressure applying arm 15.

Upon energization of the solenoid SOL the front end 31b of the arm 31 ispulled toward the solenoid SOL and the arm 31 pivots clockwise about thepin 33, so

that the piston 34 moves rightwardly in FIG. and compresses the fluid inthe pipe 38. This pushes and moves the piston 36in the cylinder 37upwardly, so that the pressure applying arm pivots clockwise in FIG. 10about the pressure applying roller shaft 17. Operation of the mechanismthereafter is substantially similar to operation of the mechanism shownin FIG. 9, so that the description thereof will be omitted, although theparts similar in function to the parts shown in FIG. 9 are designated bylike reference characters.

FIG. ll shows another embodiment of the mechanism in which the segmentalgears 26 and 28 employed in the two embodiments shown in FIG. 9 and FIG.10 are replaced by a linkage. More specifically, the segmental gears 26and 28 are replaced by links 40 and 41 and the blade mounting member 27is directly fixed to the link 40 while the blade mounting member isdirectly fixed to the link 4], with the control member 5 and the removalmember 9 being supported by the blade mounting members 27 and 30respectively.

The link has a free end portion 4011 which is connected by a connector42 to one arm portion 151: of the pressure applying arm 15. Morespecifically, the free end portion 40a is supported by the pin 24planted at one end of the connector 42 which is supported at the otherend by a pin 43 planted on one arm portion 15a of the pressure applyingarm 15. The link 41 has a free end portion 41a which is connected by aconnector 44 to the other arm portion 15b. More specifically, the freeend portion 411: is supported by a pin 45 planted at one end of theconnector 44 which is supported atthe other end by a pin 46 planted onthe other arm portion 15d.

In operation, clockwise pivoting of the pressure applying arm 15 aboutthe pressure applying roller shaft 17 causes, through the connector 42,the link 40 to pivot counter clockwise about the shaft 25, so that thefront end of the removal member 9 is brought into pressing engagementwith the periphery of the applicator roller 4. Clockwise pivoting of thearm 15 about the shaft 17 simultaneously causes, through theconnector44, the link 41 to pivot clockwise about the shaft 29, so that the frontend of the control member Sis brought into pressing engagement with theperiphery of the supply roller 1.

From the foregoing description, it will be understood that the rollers6, 4 and 1 are released from pressing engagement with one another andthe members 5 and 9 are brought out of pressing engagements with theperipheries of the rollers l and 4 respectively when the developingdevice is rendered inoperative, so that deformation of the rollers canbe precluded.

What is claimed is:

l. A developing device for copying apparatus of the diazo typecomprising:

a. an rotating applicator roller having a peripheral surface forapplying a nonvolatile concentrated developing liquid to a diazophotosensitive sheet exposed to an optical image of an original to beduplicated:

b. a supply roller having a peripheral surface maintained in pressingengagement with said peripheral surface of the applicator roller to formthcrebetween an engaging position and rotating at approximately the sameperipheral velocity as said applicator roller for supplying thedeveloping liquid to the applicator roller;

0. a control member maintained in pressing engagement with saidperipheral surface of the supply roller in a position disposed anteriorto the engaging position of said surfaces of the applicator and supplyrollers along their paths of rotation for adjusting the quantity of thedeveloping liquid supplied to the applicator roller;

d. a pressing member maintained in pressing engagement with saidapplicator roller to form therebetween a developing position throughwhich a diazo photosensitive sheet passes to be developed; and

e. a removal member maintained in pressing engagement with saidperipheral surface of the applicator roller in a position disposedposterior to the developing position along its path of rotation so as toremove any excess developing liquid from the applicator roller after adeveloping operation is performed and before any further developingliquid is supplied thereto.

2. A device according to claim 1 wherein said control member and saidremoval member are both doctor blades.

3. A device according to claim 1 wherein said control member is asqueeze roller, and said removal member is a doctor blade.

4., A device according to claim 1 wherein said control member is adoctor blade, and said removal member is a roller.

5. A device according to claim 1 wherein said applicator roller is of arubber material having a hardness in a range from 40 to and a meansurface coarseness of less than 3p.Ra.

6. A device according to claim 1 wherein said supply roller is of rubbermaterial having a hardness in a range form 40 to 60 and the averagesurface coarseness is in a range between 3 and 4p.Ra.

7. A device according to claim 1 further comprising operating means forreleasing said pressing member, said applicator roller and said supplyroller from pressing engagement with one another and releasing saidcontrol member and said removal member from pressing engagement withsaid supply roller and said applicator roller respectively when thedeveloping device is rendered inoperative, and for bringing saidpressing member, said applicator roller and said supply roller intopressing engagement with one another said control member and saidremoval member into pressing engagement with said supply roller and saidapplicator 8. A device according to claim 7 wherein said pressing membercomprises a pressing roller whose axis lies on a line with the axes ofsaid applicator roller and said supply roller, and said operating meanscomprises a lever means having a pressure rolleron one end forengaging's'aid pressing'roller, and pivotable for pressing said pressureroller against said pressing roller to bring 'mental gears for rotatingsaid gears and operatively coupled at the other end to said lever meansfor transmitting the pivoting of said lever means into rotation of saidtwo segmental gears, and actuation means for pivoting said lever meanswhereby said pressing roller,

said applicator roller, and said supply roller are brought into pressingengagement with one another and said 'control'memher and said removalmember are brought 'into pressing engagement with said supply roller andsaid applicator roller respectively.

9. A device according to claim 8 wherein said actuation means comprisesa solenoid having an actuator,

and toggle-linkage means connected to said actuator for pivoting saidlever means upon the actuation of said solenoid.

10. A device according to claim 8 wherein said actuation means comprisesa solenoid having an actuator, and an hydraulic transmission means forpivoting said lever means upon the actuation of said solenoid.

11. A device according to claim 8 wherein said crank means comprises twolinks pivotally connected at one end to each other and each connected atits other end respectively to-said lever means and one of said twosegmental gears.

12. A device according to claim 8 wherein said crank means comprises twolinks each connected at one end to said lever means and at the other endrespectively to one of said two segmental gears.

1. A developing device for copying apparatus of the diazo typecomprising: a. an rotating applicator roller having a peripheral surfacefor applying a non-volatile concentrated developing liquid to a diazophotosensitive sheet exposed to an optical image of an original to beduplicated; b. a supply roller having a peripheral surface maintained inpressing engagement with said peripheral surface of the applicatorroller to form therebetween an engaging position and rotating atapproximately the same peripheral velocity as said applicator roller forsupplying the developing liquid to the applicator roller; c. a controlmember maintained in pressing engagement with said peripheral surface ofthe supply roller in a position disposed anterior to the engagingposition of said surfaces of the applicator and supply rollers alongtheir paths of rotation for adjusting the quantity of the developingliquid supplied to the applicator roller; d. a pressing membermaintained in pressing engagement with said applicator roller to formtherebetween a developing position through which a diazo photosensitivesheet passes to be developed; and e. a removal member maintained inpressing engagement with said peripheral surface of the applicatorroller in a position disposed posterior to the developing position alongits path of rotation so as to remove any excess developing liquid fromthe applicator roller after a developing operation is performed andbefore any further developing liquid is supplied thereto.
 2. A deviceaccording to claim 1 wherein said control member and said removal memberare both doctor blades.
 3. A device according to claim 1 wherein saidcontrol member is a squeeze roller, and said removal member is a doctorblade.
 4. A device according to claim 1 wherein said control member is adoctor blade, and said removal member is a roller.
 5. A device accordingto claim 1 wherein said applicator roller is of a rubber material havinga hardness in a range from 40* to 70* and a mean surface coarseness ofless than 3 Mu Ra.
 6. A device according to claim 1 wherein said supplyroller is of rubber material having a hardness in a range form 40* to60* and the average surface coarseness is in a range between 3 and 4 MuRa.
 7. A device according to claim 1 further comprising operating meansfor releasing said pressing member, said applicator roller and saidsupply roller from pressing engagement with one another and releasingsaid control member and said removal member from pressing engagementwith said supply roller and said applicator roller respectively when theDeveloping device is rendered inoperative, and for bringing saidpressing member, said applicator roller and said supply roller intopressing engagement with one another said control member and saidremoval member into pressing engagement with said supply roller and saidapplicator roller respectively when the developing device is renderedoperative.
 8. A device according to claim 7 wherein said pressing membercomprises a pressing roller whose axis lies on a line with the axes ofsaid applicator roller and said supply roller, and said operating meanscomprises a lever means having a pressure roller on one end for engagingsaid pressing roller, and pivotable for pressing said pressure rolleragainst said pressing roller to bring said pressing, applicator, andsupply rollers into pressing engagement with each other, first mountingmeans for said removal member, second mounting means for said controlmember, two rotatably cooperating segmental gears respectively mountingsaid first and second mounting means and respectively disposed adjacentsaid applicator roller and siad supply roller such that upon rotation ofsaid two segmental gears, said removal and control members will berespectively brought into pressing engagement therewith, crank meansoperatively coupled at one end to said two segmental gears for rotatingsaid gears and operatively coupled at the other end to said lever meansfor transmitting the pivoting of said lever means into rotation of saidtwo segmental gears, and actuation means for pivoting said lever meanswhereby said pressing roller, said applicator roller, and said supplyroller are brought into pressing engagement with one another and saidcontrol member and said removal member are brought into pressingengagement with said supply roller and said applicator rollerrespectively.
 9. A device according to claim 8 wherein said actuationmeans comprises a solenoid having an actuator, and toggle-linkage meansconnected to said actuator for pivoting said lever means upon theactuation of said solenoid.
 10. A device according to claim 8 whereinsaid actuation means comprises a solenoid having an actuator, and anhydraulic transmission means for pivoting said lever means upon theactuation of said solenoid.
 11. A device according to claim 8 whereinsaid crank means comprises two links pivotally connected at one end toeach other and each connected at its other end respectively to saidlever means and one of said two segmental gears.
 12. A device accordingto claim 8 wherein said crank means comprises two links each connectedat one end to said lever means and at the other end respectively to oneof said two segmental gears.